Just based on you saying that, you haven't done enough research to self-publish. Pause--you're not ready.
Read where on Amazon, by the way? I'd love a link. Was it in the forums? I know you didn't read it in Amazon's terms, because it's not true. So either you read someone's opinion (stay away from the KDP forums and the opinions of people there, seriously) or you're interpreting the exclusivity rule to mean that you can't promote. Both are wrong.
Your book can't be available anywhere but at Amazon. You can promote it wherever the hell you want to.
You're also not going to be able to launch with Bookbub. In fact, it's unlikely that you can get a spot on Bookbub at all, let alone within a 90 day Select window, unless your book is already selling fairly well and has a decent number of reviews, has a professional-looking cover, and meets whatever other criteria they judge by. Sometime it's not quality, but full ad slots that get you rejected, too. You can try, but don't expect anything. (And if by some fluke you get a day in your 90 day window, you run the book free or at 99 cents--you have nothing else for people to buy. That's an expensive ad, especially if you're giving the book away for free. Do you know how you would maximum that exposure? Mailing list sign-ups? Teaser to the next book in the back? Do you have any kind of a plan?)
Don't count on Bookbub as part of your strategy, because it's not under your control. Plan things you can control. Later, when your book has reviews, and preferably you have some other books also with reviews and sales, start trying for Bookbub. If you get chosen, then plan a marketing strategy with other promotion around that Bookbub date, absolutely.
Also, I had a situation similar to Polenth's back when Select was new. Many, many people could tell the same story, since it keeps happening to people who want to remove books for whatever reason. I pulled one under-performing title from Smashwords and put it into Select. The Select run was a week from being over, I think, by the time I finally got the title pulled down from Sony, and only then by contacting Sony directly and pointing out how they were selling my book that they no longer had the right to sell. And then Smashwords had the audacity to scold ME for not letting them handle it (I'd been doing that for several weeks and getting nowhere, being told it would removed while watching it stay for sale).
This is one of the many reasons I recommend people to Draft2Digital.com (D2D) instead of Smashwords. Books appear and are removed much more quickly, you get paid monthly instead of quarterly, when you have a problem they respond promptly (one of my issues was emailing Smashwords with no reply, trying again in a week or two, no reply), and I've found it an overall better experience. I still publish with Smashwords, but I don't distribute through them. I make some sales in the actual Smashwords store. But I will never again let them "ship" my books anywhere. You lose control the minute you let anyone distribute for you, even D2D, but it's important to trust that distributor to follow your instructions and add a title, remove the title, change its price, update the file, etc. when you want it done. Those things happen speedily with D2D, and sometimes not at all after weeks of effort with Smash. I only use D2D for iTunes, because Apple is such a pain to deal with directly. Nook and Kobo are better to publish with directly unless you can't for some reason (Nook is still only US, I guess? I don't know offhand).
You can launch a book in Select. Some people with a new pen name have had good results with that. The trick is to be in a genre with a lot of readers, have a book in a popular sub-genre, and appropriate marketing. Inform the sites that list free books when you're about to use your Select freebie days. Or do a Kindle Countdown instead and inform the bargain-book sites.
A Select run lasts only 90 days. After that, you can add your book to other retailers. For some, it's a good launch strategy. It's impossible to say if it might be for you because I know nothing about your book. Even then, sometimes things just don't work as well for some as they do for others, without a specific reason one can easily point to. I think Select is a far better choice if a second book will follow in that 90-day window (and a third is even better). But again, genre, the look of the book, and many other things factor in.
Do some more research on pricing before you make a decision. Watch what other self-publishers do (it's always better to pay attention to what people do more than what they say, because the two don't always mesh). One nice thing about being self-published is the ability to make changes when something doesn't work. But don't take that too far and change the price after only a few days, and back and forth.
I'm a fan of Dean Wesley Smith's, have been for years, but his advice on pricing and marketing don't produce the results for him that I want to see in my business, so it's not valuable to me. It's important for me to see someone achieving the kind of results I want by doing what they're telling me to do. With all due respect to Dean and his amazing, long writing career, I don't think his pricing and marketing advice for self-published stuff is generally good advice. (If you want to sell 3-5 copies each per month of hundreds of different short fiction titles, which is the plan he endorses, maybe he's spot on.)
I feel like you're still a lot of research away from being ready to self-publish, frankly. A lot of the questions you have, you shouldn't have after some research. Don't get all your answers from AW. Check out other boards where hundreds of self-publishers hang out, ranging from raw beginners to outliers. You're not going to get all the info you need from one single place.